Summary

The workshop was organised by the DSL work package of the Global
Systems Dynamics and Policy (GSDP) project in collaboration with the
HIPERFIT project.

The aim of the workshop was to bring together researchers interested
in specification and implementation of economical and environmental
models, and computer scientists knowledgeable in Domain Specific
Languages and related methods, eager to apply their tools and theories
to "real modelling problems".

We had two days with presentations alternating between the modelling
and the methods perspectives, with sufficient space allocated for more
interactive discussion sessions where applications of the methods
could be initiated.

Thursday started with Jeremy Gibbons talking about Domain Specific
Languages for interdisciplinary research. Gibbons gave a broad
background of what DSLs are and clarified terminology relevant for
computational modelling in general. He shared his experiences from
working with DSLs for designing, executing and supporting medical
trials and opened for a discussion with a few questions:

How important is robustness of modelling in your field?

How realistic is opnenness and transparency?

Is your domain sufficiently stylized to allow a semantic framework?

After discussions over coffee we continued with Edwin Brady presenting
a more technical, tutorial style talk about "Dependent Types for
DSLs". Brady presented the dependently typed Idris language, suitable
for embedded DSLs in two senses of the word embedded. A DSL can be
embedded in Idris, but it is also aimed at implementing (and compiling
to) low-level, resoure-constrained systems (typical of embedded
systems).

After lunch Cezar Ionescu talked about "Economic equilibria in type
theory", starting with a broad, interdisciplinary overview of DSLs and
zooming in to mathematical modelling of economic equilibria. The main
message weas that "coding up" (programming) parts of economical theory
(using constructive mathematics) can help to understand the
definitions, locate "hidden" restrictions, find bugs, reformulate
definitions and results, and perhaps even suggest new results.

The afternoon session started with Nicola Botta presenting "Software
models of exchange-based economies". This tied on nicely to the
formalisation work of Ionescu but stressed that "exploratory
programming" (prototyping) is essential for fields where
specifications are incomplete, missing or ambiguous. Botta et al. have
developed a specification framework starting from and clarifying
concepts in the Gintis 2006 paper. (The overall aim is to explain if
and how the economy as a whole converges towards an equilibrium of
supply and demand in a decentralized setting.) The notation is based
on Haskell and can be seen as an embedded DSL.

Antoine Mandel continued this session with "Agent-based models in
economy", starting with a background of mathematical economics and
ending in a DSL for agents, exchange, trading, etc. Important
questions include: How to relate the results of equilibrium based and
agent-based methods? Are there middle points between the aggregate
setting (representative agents) and the full agent-absed setting? How
to structure (standardise?) the description of agent-based models?

The second day started with Carlo Jaeger talking about "Challenges to
economic modelling in the wake of the financial crisis". Jaeger
started with some context of the GSDP project, reminding us that the
first year should deliver a report on the state of the art "starting
from" the policy making view. He gave an overview of policy making of
the "big players" (European central bank, American federal reserve,
Chinese central bank, really large banks, etc.) and the models they
use. These models perform reasonably well in "steady state" but do not
predict the "mode change" to financial crises. He believes the next
step is to express the "frame conditions" of the different modes in a
DSL. Jaeger also provided a historical overview of mathematical
economics.

After the break Fritz Henglein presented "DSLs for the financial
sector" starting with his own introduction to DSLs as a mothodology
for software development: first write down / specify the structure of
the domain (as a DSL), then express your problem in this
language. Already without any computer interpretation this helps
clarifying (framing) the problem, but then we can also implement one
or more complementing solvers or analysers of the problem. As an
example he presented a family of DSLs for "Enterprise Resource
Planning". He ended with presenting the newly started HIPERFIT
research project and pointed us to a concrete "policy making"
connection: a "Securities and exchange commission" RIN 3235-AK37
recommends executable models (in Python) as a way of specifying
evaluation of asset-backed securities.

In the last session, after lunch on Friday, Sinan Gabel (from Nordea
Denmark) presented "Crossroad between banking, regulation and
technology". He started with an overview of how High Frequence Trading
is driving hardware and algorithm investments in the banking sector.
To enable proper risk management, models of financial products need to
be transparent, that is, clearly specified.

Dates: 2011-06-16 (starting at 09.00) and 2011-06-17 (ending at 16.00)

Place: Marstrand (near Gothenburg, Sweden)

Schedule:

For those eight of us who arrive on Wednesday 2011-06-15, we will be in Hotel Lökeberg for the first night and then transfer to the workshop venue.

Wednesday, 2011-06-15

19:00:

Dinner at Hotel Lökeberg (the those who have arrived)

Thursday, 2011-06-16

8.30:

Transfer from Lökeberg to Grand Hotel Marstrand (the workshop venue) for those arriving on Wed.

The speakers should aim for 30-40 minute talks to leave ample time for discussions and group work. Style-wise I'd like all presentations to maximise the interaction with the other participants - perhaps suggest a few "exercises" to solve or a demo or something else in the style of "a workshop / a summer school / teamwork" rather than just "a lecture".

The session chair introduces the speaker, keeps time and chairs the discussion.

Jansson will take notes which will later be transformed into first a "workshop report" and second a "work package deliverable" towards the GSDP project annual report.